California's Groundbreaking Plan to Reduce Embodied Carbon with New Building Codes
Embodied carbon refers to the greenhouse gas emissions that are produced by building materials over their entire life cycles—including extraction, manufacture, transportation, installation, maintenance, and disposal. Today, building emissions constitute 40% of California’s greenhouse gas emissions posing significant opportunities for carbon reduction measures.
On August 2, 2023, California became the first state in the nation to set general code standards that require the reduction of embodied carbon emissions in the design and building process for both commercial buildings and schools. The code additions are amendments to the 2022 California Green Building Standards Code (CALGreen), Part 11, Title 24.
The new additions, which take effect on July 1, 2024, will impact new construction, remodeling, or adaptive reuse projects on public and private buildings with a combined floor area of 100,000 square feet or greater and school buildings of 50,000 square feet or greater.
The standard provides three compliance paths to meet the new codes:
Reuse: When reusing a building, maintain at least 45% of the existing structure and enclosure.
Whole Building Life Cycle Assessment: Demonstrate a 10% reduction in global warming potential (GWP) compared to a reference building of similar size, complexity, and use.
Product GWP Compliance: Products under building codes must comply with maximum GWP values and environmental product declarations (EPD) are to be included on construction documents.
California Building Standards Commission plans to require compliance down to 50,000 square feet for commercial buildings by January 2026, and will continue reducing so that by 2030, buildings at multiple scales will be required to account for their embodied carbon emissions. This will, in turn, stimulate other states to follow suit and introduce code changes to reduce embodied carbon.
Scott Gaudineer, president of American Institute of Architects (AIA) California, said, “It can take up to 80 years to overcome embodied carbon’s impact through strategies that reduce energy usage or operational carbon; the planet doesn’t have that time. [The new standards] codify a cultural shift: to meet decarbonization timelines set by California law, embodied carbon must be reduced in addition to operational carbon.”
The new embodied carbon building code legislation is a major milestone in California’s journey to tackle the ambitious carbon commitments the state has made. AIA California will facilitate programs over the coming months to advance zero-net-carbon literacy and educate industry professionals on the new codes.
